Our overall goal is to understand the molecular basis of cell movement. Improperly regulated cell movement is involved in many diseases states including metastatic cancer and inflammation. Cell movement involves the remodeling of the actin cytoskeleton in response to external cues. We are studying a protein that transduces signaling information to the actin cytoskeleton. This protein, N-WASP, appears to act as a switch that, given the appropriate upstream signals, targets and activates the actin polyrnerization machinery at the proper sites. To understand how N-WASP is localized , we are examining it's N-terminal domain, which is thought to be critical for targeting. We are attempting to identify ligands for the domain and to characterize ligand specificity. We will follow it's localization in vivo in chemotaxic cells using domains fused to green fluorescent protein. To understand how N-WASP acts as a molecular switch, we are attempting to identify and characterize repressive intramolecular interactions and to determine the structure of N-WASP alone and in the presence of activating ligands such as CDC42.